Mobile natural gas leak detection

Pipeline networks, especially ones which cross entire countries and run for thousands of miles, will always present an issue when it comes to leakage. The variety of factors at play in operating and maintaining a network, including aging infrastructure, network pressures and the efficiency of any maintenance regimes, mean that leakage in a network can at best only ever be controlled rather than eliminated.

With Australia’s abundant supply of gas — our third largest energy resource — predicted to last more than 50 years based on current production, there are many reasons why natural gas leaks from oil and gas networks need to be kept under tight control. Most pressingly, with the Paris Agreement demanding that industry does more to keep its environmental emissions under control, leaking natural gas pipelines have been identified as a major source of methane emissions that are harming the environment.

Financially, gas leaking from pipelines also represents the loss of billions of dollars of revenue every year, both in terms of direct product and the effort and costs involved in replacing it.

It can also pose a risk to safety, not just on the industrial sites that produce it but also in the wider community. Incidents such as the Varanus Island, Western Australia, gas crisis in 2008 where — in a state heavily reliant on a continuous supply of gas for industrial processing, manufacturing, residential use and electricity generation — the sudden loss of nearly half of its gas supply had immediate social impacts, and significant short- and long-term economic effects. Many businesses were forced to curtail or cease operations, resulting in workers being stood down and the government requesting that businesses and householders conserve energy usage. With the worldwide regulations in place, operators must increasingly ensure they are using the most effective technology to help locate, measure, intervene and control natural gas leaks at all points in the distribution network.

Sniffing out leaks

When it comes to detecting gas leaks, various approaches are used, with options including continuous monitoring using in-situ sensors, periodic surveys using handheld devices, and mobile analyser platforms. Whilst the first two options offer their own set of advantages, the third category — mobile analyser platforms — is offering exciting opportunities for improved gas leak detection over much wider areas in a greatly reduced timeframe.

An example is the ABB Ability Gas Leak Detection System, which combines an analyser (using patented laser-absorption technology) with various solutions, ranging from a portable backpack variant through to car-, aircraft- and drone-based versions that allow methane emissions to be accurately tracked back to their source. At the heart of the system is a patented high sensitivity analyser capable of measuring both methane and ethane concentrations at rates of up to 5 Hz. The analyser uses a principle called Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS), which works by using a tunable laser source that produces light at a suitable wavelength for interacting with the gas being analysed.

The laser enters a highly reflective mirrored cavity, where it is reflected thousands of times before exiting onto a photodetector. This creates an effectively long optical path amounting to many kilometres. By changing the wavelength over which the laser operates, the concentration of the gas can be measured with high precision. With a sensitivity over 1,000 times higher than conventional leak detection technologies, the OA-ICOS method permits the analyser to detect single parts per billion (ppb) levels of methane and ethane every second, enabling variations in atmospheric concentrations to be quickly measured over long distances where other technologies would be ineffective.

Taking gas leak detection mobile

While in-situ gas leak detection sensors and equipment can detect the presence of a leak, locating it can often require additional effort, including the deployment of maintenance resources using handheld survey equipment. As well as incurring time and cost, this approach can pose a potential risk to safety as people are exposed to potentially high levels of explosive gases.

Today’s gas detection sensors can be fitted to road vehicles, aircraft or drones.

A mobile gas leak detection solution combining a high sensitivity analyser such as the one described, with a vehicle or airborne platform, can help to overcome this challenge, enabling leaks to be quickly traced to the source with relatively little effort.

In ABB’s system, for example, data from the analyser is combined with GPS coordinates from mapping software, along with wind speed and direction from an anemometer, and fed into a laptop that performs the leak analysis and provides a real-time picture of the area surveyed overlaid with details on methane concentrations and potential leak points. This information can be used to produce detailed digital reports allowing the operator to take the necessary measures to find and fix the leaks.

Keeping an eye on emissions

With industries across all sectors under growing pressure to reduce the environmental and societal impact of their operations, the use of the latest emissions measurement technologies is becoming increasingly important. The UAV-based analyzer (HoverGuard) is just one of a number of options available to help industrial operators measure gas concentrations more accurately, with developments in measurement and digital technologies increasingly combining to offer highly accurate measurement solutions that are at the same time easy to use and integrate.

As a global leader in continuous emission monitoring with over 60,000 systems installed in more than 50 countries worldwide, ABB can help you to ensure your operation meets the relevant regulatory and environmental standards. Its Continuous Emissions Monitoring Systems (CEMS) offer complete solutions for continuous recording and evaluation of emission data in all industries. The systems provide important information for the environmental and economic operation of production facilities across multiple industries, from oil and gas through to paper, food and beverages, and cement for the construction industry.

For more information about how ABB can help to make emissions measurement easy, visit www.abb.com/measurement.

Top image: ABB's MobileGuard mobile gas leak detection vehicle.